二、Button

一：前端页面显示

<?xml version="1.0" encoding="utf-8"?>

    

二：后台调用Button的事件

主要三种事件：1.点击事件  2.长按事件  3.触摸事件

package com.example.mybutton;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "leo";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

       Button btn= findViewById(R.id.btn);

       //点击事件
        btn.setOnClickListener(new View.OnClickListener(){
           @Override
           public void onClick(View view) {
               Log.e(TAG,"onClink:");
           }
       });

       //长按事件
       btn.setOnLongClickListener(new View.OnLongClickListener(){
           @Override
           public boolean onLongClick(View view) {
               Log.e(TAG,"onLongClick:");
               return false;
           }
       });

       //触摸事件
       btn.setOnTouchListener(new View.OnTouchListener(){
           @Override
           public boolean onTouch(View view, MotionEvent motionEvent) {
               Log.e(TAG,"onTouch:"+motionEvent.getAction());
               return false;
           }
       });

    }

    public void leoClick(View view) {
        Log.e(TAG,"OnClink:");
    }
}

　　三：实现悬浮或者点击时，样式的切换

入下图所示，通过drawable中selector实现图标的更改